The present invention relates to a technology for recording and playing back signals such as video and audio signals into and from an erasable recording medium such as an optical magnetic disc, a variable phase disc and a magnetic disc.
By virtue of development of band compression technologies represented by the recently introduced MPEG (Moving Picture Experts Group) compression/coding technology, signals such as audio and video signals can now be recorded into a large capacity recording medium such as an optical magnetic disc for a playback operation of a long time.
When a signal is recorded into such a recording medium, the signal undergoes a band compression/coding process, being recorded in sector units. The signal is then recorded into free areas on the recording medium.
Traditionally, a signal continuous in the time axis direction resulting from typically editing work such as an audio or video signal is recorded into a recording medium, being split into segments as shown in FIG. 21(1). In the figure, the symbol # on each of the segments indicates the order number in an operation to play back the signal. While the segments of the signal are arranged along a straight line as shown in the figure, the signal is actually recorded on a track having a spiral shape or concentric tracks on the recording medium.
Consider a playback operation in which segment #5 is reproduced after segment #4. In this case, a reproduced signal generated by a read pickup is broken due to a seek time, a rotation wait time and a settle time which are required between segments #4 and #5. The seek time is a period of time it takes to move the read pickup in a so-called track jump to a track in area where segment #5 is recorded. On the other hand, the rotation wait time is a period of time it takes to wait for the read pickup to arrive at the position of a target sector on the track. Finally, the settle time is a period of time it takes the tracking servo of the read pickup to get settled.
In order to prevent a playback signal eventually generated by the recording/playback apparatus from being broken even if the reproduced signal generated by the read pickup is unavoidably broken as described above, a read buffer memory is provided for storing in advance a signal read out from the recording medium. The signal stored in the read buffer memory is used for filling up the time gap between two consecutive segments, that is, a period of time during which no reproduced signal is generated by the read pickup. The signal stored in the read buffer memory is then output when the reproduced signal generated by the read pickup is broken.
In the case of a recorded signal split into a large number of segments as shown in FIG. 21(2), however, it is quite within the bounds of possibility that the amount of data stored in advance in the read buffer memory during the time is not large enough to be used for filling up a time gap between two consecutive segments. As a result, the eventual playback signal can not be generated continuously.
The present invention addresses the problems described above. It is thus an object of the present invention to provide a technology that makes a continuous playback operation possible by assuring that the amount of data stored in a read buffer memory is large enough for eliminating a playback time break through reduction of the number of seek operations.
In order to achieve the object of the present invention, the present invention provides a signal recording method whereby, in an operation to record a signal onto a recording medium, the signal is recorded in continuous free areas each having a size equal to or larger than a predetermined recording/playback time length.
In addition, the present invention also provides a signal recording/playback method wherein, in an operation to insert an additional signal having a length smaller than a predetermined recording/playback time length into a point of insertion in an area on a recording medium already occupied by an existing signal, the signal recording/playback method is implemented by executing the steps of:
newly allocating a continuous free area on the recording medium with a size of at least the equivalence of the predetermined recording/playback time length to the additional signal;
recording the additional signal in the continuous free area; and
filling up the rest of the continuous free area with a portion of the existing signal adjacent to the point of insertion.
Furthermore, the present invention also provides a signal recording/playback method wherein, in case a signal already recorded on a recording medium has a continuous segment smaller in size than an equivalence of a predetermined recording/playback time length, the signal recording/playback method is implemented by executing the steps of:
newly allocating a continuous free area on the recording medium with a size of at least the equivalence of the predetermined recording/playback time length to the segment;
relocating the segment to the continuous free area; and
filling up the rest of the continuous free area with a portion of the signal adjacent to the segment.
On the top of that, the present invention also provides a signal recording apparatus for recording a signal onto a recording medium, the apparatus comprising:
a 1st means for recognizing a continuous free area on the recording medium with a size equal to or larger than a predetermined recording/playback time length; and
a 2nd means for executing control to record a signal onto the continuous free area.
In addition, the present invention also provides a signal recording/play back apparatus for recording and playing back a signal onto and from a recording medium, the apparatus comprising:
a 1st means for recognizing a continuous free area on the recording medium with a size equal to or larger than a predetermined recording/playback time length; and
a 3rd means for executing control to record a signal, which is supposed to be newly inserted into a point of insertion in an area on the recording medium already occupied by an existing signal, onto the continuous free area and to fill up the rest of the continuous free area with a portion of the existing signal adjacent to the point of insertion.
Furthermore, the present invention also provides a signal recording/play back apparatus for recording and playing back a signal onto and from a recording medium, the apparatus comprising:
a 1st means for recognizing a continuous free area on the recording medium with a size equal to or larger than a predetermined recording/playback time length; and
a 4th means for executing control to relocate a continuous segment of a signal already recorded on the recording medium having a size smaller than a predetermined recording/playback time length and to fill up the rest of the continuous free area with a portion of the already recorded signal adjacent to the segment.
On the top of that, the present invention also provides a signal recording medium wherein a signal is recorded into continuous areas each having a size equal to or larger than a predetermined recording/playback time length.
According to one aspect of the present invention, there is provided a signal recording apparatus provided for recording a signal onto a recording medium wherein:
a 1st means is used for recognizing a continuous free area on the recording medium with a size equal to or larger than a predetermined recording/playback time length; and
a 2nd means is used for executing control to record a signal onto the continuous free area.
In addition, according to another aspect of the present invention, there is provided a signal recording/play back apparatus for recording and playing back a signal onto and from a recording medium wherein:
a 1st means is used for recognizing a continuous free area on the recording medium with a size equal to or larger than a predetermined recording/playback time length; and
a 3rd means is used for executing control to record a signal, which is supposed to be newly inserted into a point of insertion in an area on the recording medium already occupied by an existing signal, onto the continuous free area and to fill up the rest of the continuous free area with a portion of the existing signal adjacent to the point of insertion.
On the top of that, according to a further aspect of the present invention, there is provided a signal recording/play back apparatus for recording and playing back a signal onto and from a recording medium wherein:
a 1st means is used for recognizing a continuous free area on the recording medium with a size equal to or larger than a predetermined recording/playback time length; and
a 4th means is used for executing control to relocate a continuous segment of a signal already recorded on the recording medium having a size smaller than a predetermined recording/playback time length and to fill up the rest of the continuous free area with a portion of the already recorded signal adjacent to the segment.